Thousands of dolphins were spotted off the coast of San Diego by passengers aboard a tour boat, which then followed the "super mega-pod" for more than an hour.

“They were coming from all directions, you could see them from as far as the eye can see,” said Captain Joe Dutra of Hornblower Cruises to San Diego’s NBC affiliate, NBC7.

He estimated that 100,000 dolphins, adult and juvenile, were swimming in what he called a “super mega-pod” that stretched more than seven miles long and five miles wide, the television station said.

“They were coming from all directions, you could see them from as far as the eye can see,” Dutra told the station. “I’ve seen a lot of stuff out here … but this is the biggest I’ve ever seen, ever.”

It’s not unheard-of for that many dolphins to gather, though wildlife specialists told the TV station that they usually travel in groups of no larger than 200. Sometimes, though, schools join together, said Sarah Wilkin, a marine mammal expert, to NBC.

The incident reminded boat captain Dave Anderson of one such pod that he had encountered.

"It's one of the most amazing things I've ever seen," Anderson told the Los Angeles Times, likening the phenomenon to being in the middle of a herd of wild horses.

“You had to be there to experience it,” Dutra said. “It was truly spectacular.”

Luckily we’ve got the next-best thing: a video taken by one of the many guests aboard the boat, which was in fact on a whale-watching tour.